When I first started growing years ago, it was with autos....I couldn't keep my hand off of'em...I tried topping, fimming and everything else I read about.....found out neither helped anything and only stunted my plants, resulting in small yeilds almost every time....Autos have changed in a lot of ways since then but still do no tthink it is any advantage at all to top or anything else...I lst a lot to control upward growth and promote lower buds but ain't topped one in years...good luck with ya stuff....and don't believe everything ya see on yu-tube.